Boracite

1. n. A mineral of a white or gray color occurring massive and in isometric crystals; in composition it is a magnesium borate with magnesium chloride.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.